1. Field of the Invention
The present invention relates to a control apparatus that controls stapling and an image forming apparatus that performs stapling.
2. Description of the Related Art
Conventionally, there has been provided an image forming apparatus that has a staple setting as one of print settings. In such an image forming apparatus, a user can set a stapling position indicating which of four corners and upper and lower sides of a print product is stapled via a printer driver screen of a personal computer (PC) or an operation unit of the image forming apparatus.
However, there is an upper limit to the number of staplable sheets by one staple on a set of recording papers that is a print product. Many image forming apparatuses store maximum numbers of staplable sheets as fixed values in storage units, and do not execute stapling when the numbers of recording sheets exceed the maximum number of staplable sheets.
Japanese Patent Application Laid-Open No. 11-192766 discusses an image forming apparatus that performs control to bind recording sheets as many as possible by one staple by varying the maximum number of staplable sheets based on quality of the recording sheets to be stapled and characteristics of the staple.
In the conventional technology, however, the maximum number of staplable sheets is fixed irrespective of a stapling direction on the set of recording papers. As a result, depending on a stapling direction, strength of stapling is lower even on the same set of recording papers.
Specifically, as illustrated in FIG. 7, when first to last pages are stapled on the upper left side of a set of sheets 501 including three recording sheets on which the image forming apparatus has printed landscape images, a possibility that the sheets will be easily unstapled is low even if the user turns over the sheets upward and obliquely to the left.
On the other hand, when last to first pages are stapled on the upper left side of a set of sheets 502 including three recording sheets on which the image forming apparatus has printed landscape images, a possibility that the sheets will be easily unstapled becomes high if the user turns over the sheets upward and obliquely to the left.
Thus, at the stapling position, depending on a turning-over direction of the set of sheets to be stapled, the staple may easily fall off, necessitating time and labor for re-stapling.